The Federal Aviation Administration has proposed a civil penalty of $400,000 against cargo airline Kalitta Air for allegedly operating flights in a prohibited region when certain aircraft have a faulty multimode receiver.

The agency announced Friday that Kalitta Air, based in Ypsilanti, Michigan, used prohibited procedures on 44 flights between late December 2022 and Jan. 26, 2023. The Boeing 777 freighter did not have the required software needed to correct a fault in the navigation equipment. Multi-mode receivers receive land-and-satellite-based signals that enables precision navigation.

The violation stems from a 2020 order prohibiting aircraft with Collins GLU-2100 multimode receivers that had a specific type of software installed from operating in a part of the world where the loss of global positioning system data, or degraded GPS accuracy, was possible.

“This improper mapping within the operational software, if not addressed, could, during a high-precision approach with a GPS error, result in controlled flight into terrain,” the 2020 airworthiness directive said.

Airlines were instructed to revise flight manuals informing pilots of the banned areas if the navigational system can’t calculate its position within three-tenths of a nautical mile.

Kalitta, which operates five 777s for DHL Express, has asked to meet with the FAA to discuss the case. It is possible the penalty could be negotiated down. The company did not respond to a request for comment by time of publication.

Collins Aerospace has since released new software to rectify issues with the GPS software.